Mold for metal-casting.



No. 636,952. Patented Nov. 19, 4901-. C. S. PRICE& G. E. THAGKRAY. MOLDFUR METALQASTING. (Application filed July 20, 1900.) (No Model.)

Unteren ASTATES PATENT OFFICE.

CHARLES S. PRICE AND GEORGE E. THACKRAY, OF VESTMONT, PENNSYLVANIA.

MOLD FOR METAL-CASTING.

SPECIFICATION forming part of Letters Patent No. 686,952, dated November1 9, 1901. Application tiled July 20,. 1900. Serial No, 24.271. (Nomodel.)

GEORGE E. THACKRAY, citizens of the United States, residing in theborough of Westmont, in the county of Cambria and State of Pennsylvania,have invented certain new and useful Improvements in Molds forMetal-Casting; and we do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

The increase in concentrated wheel-loads in railway service has beenvery considerable during the past few years, and owing to this trafficthe destructive action on roadbeds and rolling-stock has become more andmore marked and of greater extent in a given time than that which hasbeen usual heretofore.

It is the object of our invention to provide an apparatus for themanufacture of steel rails in which those portions of the head that aresubject to wear are formed of hard steel, which gradually merges into asteel of softer quality, which forms the lower portion of the head, theweb, and the ianges. A rail so constructed is well adapted to resist thewear and abrasion due to the passage of heavilyloaded wheels, and at thesame time it is tough, reliable, and well suited to withstand the loadswhich it has to carry by reason of the softer quality of its lowerportions.

In carrying out our improvement we use a mold one portion of which islined with a special carbonaceous material, so held in position thatwhen steelvis poured into the mold part of the ingot is in contact withsaid carbonaceous lining and by reason thereof absorbs a certain amountof carbon, which has the effect of making that portion so treated harderthan other portions of the ingot. This carbonaceous lining may beapplied to any or all sides of the ingot-molds or any portion thereof inorder te properly locate the harder portions of the ingot, as may bereadily understood. It maybe applied to the surfaces of ordinarycast-iron molds by means of a removable plate fitted to one of itssides, secured thereto by means of bolts passed through holes in thesides of the molds, said bolts being provided with keys, nuts, or

other means for securing a bearing against the outer surfaces of themold in such a way as to hold the plate securely therein. This removableplate may be provided with projecting studs, prickers, scores,indentations, or other irregularities so designed as to provide asuitable base upon which to hold the carbonaceous lining, one of theadvantages of said plate being its portability, so that it can bereadily handled, made up, dried, and placed in position in the mold.

We do not limit ourselves to the exact arrangement of lining shown inthe drawings, as it may also be extended over one side and portions ofthe two adjoining sides, or it may cover all sides in case an ingot isdesired the central portion of which shall be softer than the exterior.Our lining may also be used in connection with a mold of any kind and onall or any portions of the inner surfaces thereof, dependent upon thedesired position of the highly-carbonized steel, as hereinbefore noted.

We have found by practice that charcoal is more readily soluble inheated steel than is coke-dust; but in order to make a lining with itthat shall be sufficiently porous to allow the escape of the gasesevolved during and after the pouring of the steel We use a smallproportion of coke-dust in connection with the charcoal lining, so thatit shall have the needed porosity. In order to provide the necessaryporosity for the escape of gases from the lining in certain other cases,We mayprovide it with longitudinal vents G, formed by the withdrawal ofwires previously placed in proper position, after the manner of usualfoundry practice in this respect. By varying the proportions ofcoke-dust and charcoal we are able to form a lining which willgive therequired degree of carbonization dependent upon the ease of solubilityof said mixture.

It is essential to the proper action of our carbonaeeous lining that itshall be as free as possible from gases that would be evolved by theapplication of heat, and to further insure a proper result the liningshould preferably be sufticien tly porous or so vented as to allow anygases formed during and after the pouring to escape without damage tothe ingot or lining.

Although our invention is shown in the drawings in connection with themanufacture of rails having the head harder than the web or flanges, wedo not limit ourselves to its use in this connection solely, but it maybe applied to the manufacture of any articles of steel in which it isdesirable to have hard portions to resist wear and softer ones to insurecertain toughness and resistance to impact, as may be readily understoodby one skilled in the art.

While the mannerof preparation of our car bonaceous lining is to acertain extent immaterial, we prefer to thoroughlyincorporate thematerials in a dry state, and in case water is needed for proper actionof the binding material this is supplied after the dry mixing has beenthoroughly effected. The mixture is spread on the plate covering thosesurfaces of the mold corresponding to the portions of the ingot or othershape which are desired to be hardened, after which the lining isproperly dried or baked in an oven, the heat being raised toward thelast in order to thor.- oughly drive off all the moisture and as much ofthe volatile matter of the compound as is consistent with retaining itsstrength after the baking operation. In preparing the mixture in whichcoal-tar pitch is used as a binder in connection with coke or charcoalwe prefer to first mix the binder and carbonaceous matter together in adry condition in a finelygranular form, and after being thus thoroughlymixed together they may be heated and further mixed in a suitable pan,the effect of this heating being to soften the pitch, so as to make thewhole mass coherent, after which it may be spread on the plate-surfacesas desired and then baked, as heretofore described.

We have found the following proportions of material give excellentresults and are what we prefer to use: coke-dust, eight parts, hardcoal-tar pitch, one part; or charcoal, eight parts, hard coal-tar pitch,one part; or charcoal, seven parts, coke-dust, two parts, coal-tarpitch, one part.

In addition to the above mixtures we have found that in certain cases acomposite lining is useful, the face of which is composed principally ofcharcoal, the backing being made of coke-dust, both bound together withcoal-tar pitch. In making this compound lining the backing is rstapplied to the face of the plate, whose surface is roughened inanyvsuitable way, after which the charcoal facing is applied to therequired thickness, thus making a lining the outer face of which isformed principally of charcoal, which is spread upon the coke backing.We have found that charcoal is more readily soluble in steel thancoke-dust; but after being baked in its ordinary powdered condition itit is not sufficiently porous to give vent to the gases evolved duringand after the pouring, nor does it bake suiciently hard to make the bestlining. By using the compound lining, as above described, we obviatesome of the difficulties connected with the use of charcoal for theentire body of the lining, as the coke backing is sufciently porous togive proper vent, besides which it resists heat better than charcoal,and thus produces a casting of better surface. After forming an ingot bypouring molten steel into a mold provided with an entire or partialcarbonaceous lining, as above described, said ingot after stripping maybe heated, if necessary, hammered, rolled, forged, or otherwise workedto produce rails, wheels, armorplate, machinery, slides,or guides, or,in fact, any articles for which it is adapted in the arts. After pouringthe steel in the mold, as described, we prefer to allow it to remainthere for some time in order that it may properly absorb the carbon,which absorption continues during a considerable range of temperature.It is manifest, however, that by stripping the ingot after a long orshort exposure to the carbonizing material the hardening effect may bemade more or less within a certain range.

Having given this general description of our invention, we will now, tomake the matter more clear, refer to the annexed drawings, which formpart of this specification, and in which like letters refer to likeparts.

Figure l is a side elevation of a mold provided with our carbonaceouslining mounted on a removable plate, showing a steel ladle in positionfor pouring into it. Fig. 2 is a longitudinal section taken on the line2 2 of Fig. 1. Fig. 3 is a separate perspective View of thepricker-plate shown in connection with the mold in Fig. 2. Fig. 4 is across-section of a rail, in which the upper hardened portion of the headis indicated by heavy shad ing. Fig. 5 is a vertical section of the moldA, showing an arrangement for securing the pricker-plate E thereto; andFig. 5a is a side view of the same. Fig. 6 is a horizontal sec tiontaken on the line 10 l0 of Fig. 5. Fig. 7 is a cross-sectional view ofthe plate and its lining, showing the longitudinal vents.

In the different figures, A isa metallic mold provided with acarbonaceous lining C.

E is a plate provided with a number of prickers e2 e2 and bolts c c, bymeans of which it is secured to the mold A with the aid of keys c e'.

ct represents eyebolts secured to the upper portion of the pricker-plateE for the purpose of lifting it.

Referring to Figs. 5 and 6, which show one arrangement for securing thepricker-plate E to the mold A, e is a key-bolt formed with an outwardlytapering head b, which is adapted to drop into the slotted hole c, theupper part of this hole being of sufficient size to allow suchintroduction. In this arrangement the key e is normally in a'horizontalposition, in which respect it differs from the key c of Figs. l and 2.

Instead of the above arrangement the bolt IOO e may be fixed to theplate E, as shown in Figs. 2, 3, and 7.

Referring to Fig. 4, Rrepresents the upper hardened portion of arailmade by our process, while R represents the bottom flange, which issofter than the upper portion of the head, as indicated by the shading.

In Figs. l and 2, B is a mold-stool.

XVe are aware that steel has been hardened both locally and throughoutbythe slow cement-ation process in contact with carbonaceous material bythe aid of heat, and we are also aware that articles of iron and steelhave been produced with hard portions or faces by welding hardermaterial thereto, either in the usual Way or by pouring molten steel oriron against previously-heated pieces of hard steel properly located inthe mold; but both of these processes are quite expensive, while thelatter especially requires a long period of time for conducting theoperation properly, and we do not claim such process or apparatus forconducting said processs; but

1What we claim, and desire to secure by Letters Patent, is-- l. A moldprovided with a metal plate forming part of its interior surface, saidplate having a soluble carbonaceous lining, and the plate and mold beingprovided with coperating fastening means, whereby the plate may bedetached and resecured in position.

2. A mold provided with a metal plate forming part of its interiorsurface, said plate having a soluble carbonaceous lining provided with aseries of longitudinal vents, and means fordetachably securing theplatein the mold.

3. A mold provided with a metal plate forming part of its interiorsurface, said plate having a carbonaceous lining composed of a mixtureof crushed coke and coal-tar pitch, a series of longitudinal ventswithin said lining, and means for detachably securing the plate in themold, substantially as shown.

In testimony whereof we afiix our signatures in presence of twowitnesses.

CHARLES S. PRICE. GEORGE E. THACKRAY. Witnesses:

D. J. JONES, G. H. EVANS.

